A Systematic Review of the Literature on the Relationships between Chronic Diseases and Food Insecurity

Abstract

Background: The association between food insecurity (FI) and obesity is now so well documented that scholars have dubbed it the "'new' food insecurity" and cited it as a leading cause of increased chronic disease (CD) risk. Here, the chain of causality is assumed to be FI → obesity → CD. However, this model overlooks the possible direct associations between FI and CD independent of obesity. Aim: This study assessed the literature on relationships between FI and CD. Methods: We conducted a systematic literature review of electronic databases. Selection criteria were designed to elicit studies that assessed FI and CD using a measure of CD other than obesity. Results: Fifty one articles met the inclusion criteria. Forty-five studies (87%) reported a statistically significant association between FI and CD, but only 15 adjusted for obesity. The association was less consistent for asthma and dyslipidemia than for diabetes, hypertension, and other diet-related CDs, and most were conducted in the USA or Canada. Conclusion: There is a body of literature documenting relationships between FI and CD, but it is heavily biased toward Western nations, ecological study designs, and type 2 diabetes as the CD of focus. A small subset of the literature controls for BMI, demonstrating that a portion of the FI-CD relationship cannot be fully explained by obesity. Possible direct pathways linking FI and CD include systematic effects of poverty that accompanies FI, micronutrient deficiencies, and environmental exposure to toxins; however, exploration of these alternative pathways is limited by study designs that fail to include obesity as a control variable.